Electric switch gear



' G.l PAILIN ELECTRIC SWITCH GEAR May 24, 1932.

Original Filad Oct. 19, 1929 112g A ./,CZA/

, HLS Attorng.

.59 of my invention the switch when operated to lll Patented May 24, 1932 UNITED STATES PATENT OFFICE GEORGE PAIIIN, OF MANCHESTER,VK`ENGLAND, ASSIGNOR TO GENERAL ELECTRIC COM- PANY, A CORPORATION 0F NEW YORK ELECTRIC SWITCH GEAR.

Application led October 1,9, 1929, Serial No. 400,988, and in Great Britain January 9, 1929. Renewed .March 11, 19355 sure between the plugs and sockets shall exist in order to ensure efficient electrical connection, but this pressure must not interfere with or hinder the operation of readily making and breaking the electrical connection between the withdrawable and fixed portions of the switchgear. The withdrawable portion may comprise a circuit breaker, a. switch,

switch fuse, a transformer and switch or other arrangements involving apparatus for vmaking and breaking electric circuits, and

such may be of the oil, air or other types.

A principal object of my invention is theV provision of means incorporated in the cooperating electrical contacts of the fixed and movable portions of the switchgear for increasin the pressure between the coacting contactlng surfaces to insure efficient electrical contact when the movable portion is in its circuit closing position, and for decreasing the aforesaid pressure in response to movement of the movable or withdrawable portion towards its open circuit position, thereby facilitating withdrawal thereof.

In accordance with my invention, the switch or circuit breaker mounted upon the withdrawable portion of the switchgear when operated to close the circuit imposes pressure, by means of a member actuated by the switch, between the electrical contacts which connect the withdrawable and stationary parts of the switchgear so that good electrical connection between said parts is ensured by the act of closing the switch.

Further, in accordance with another aspect break the circuit, releases the pressure between the aforesaid contacts, so facilitating the withdrawal of the contacts from engagement wit-h each other. With the aforesaid arrangement, it willbe apparent that pressuresuflicient to ensure good electrical connection is applied only between the electrical contacts when it is required, that is, when Athe electrical circuit is completed.

My invention will be more fully set forth in the following description referring to the accompanying drawings, and the features of novelty which characterize my invention will be pointed out with particularity in the claims annexed to and forming a part of this specification.

Referring to the accompanying drawings, Figs. l and 2 are elevational sectional views of switchgear embodying my invention wherein the means for breaking the electric circuit between the withdrawable portion and the live contacts are illustrated in the open and closed circuit positions respectively, and

Fig. 3 is a cross-sectional view taken on the line l-B of Fig. l.

ln the illustrated application of my invention to the draw-out type 0f switchgear, in which plug and socket electric connections are employed between the withdrawable and fixed parts, the plug or equivalent member l is split or divided at one end into a number of segments 2, the end of the plug so divided entering within a solid socket 3. Within the end of the plug disposed within the socket 3 are arranged two wedge shaped members, as the cones 4 and 5 with their apices adjacent each other, or together as illustrated. The cones 4 and 5 are mounted upon a central stem or sleeve 6, the cone 4 being fixed to the sleeve 6 and the cone 5 being freely slidable thereon. The annular space between the outer surfaces of the cones and the internal surface of the plug is filled with suitable pressure-transmitting material,

as the balls 7. The cone 5 which is slidably versely of the sleeve and through slots a therein so that the key may move longitudinally with respect to the sleeve. Such longitudinal movement is effected by' a member, as the rod 11, which passes centrally of and throughv the plug to a position where it is adapted to be engaged by the cross bar 12 of the switch when such bar is in the circuit closing position, as illustrated in Fig. 2.

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When thereforethe switch is closed, pressure is applied through the rod 11 and spring 8 to the movable cone 5 and so to the pressuretransmitting material or balls within the plugsegments. The balls accordingly tra-nsmit this pressure so as t0 apply an even expansive or radial ressure to the segments 2 of the plug, there y forcing them into firm contacting engagement with the contacting surface of socket 3 to insure the desired good electrical contact between the plug and socket.

When the switch is opened the cross bar 12 is moved downwardly and the spring pressure applied through the bar 12 and rod 11 is removed from the movable cone 5 and the balls 7, thereby releasing the pressure on the plug segments. Accordingly, the withdrawal of the plug from the socket may be readily eected without difficulty.

It will be seen that with my improvement, the plugs and sockets of truck-type switchgear are moved into or out of engagement as readily as with the ordinary types of plugs and sockets with the added advantage that when the circuit through the same is' completed, a sulcient additional pressure is applied between the said parts to ensure the desired electrical connection to carry comparatively heavy currents in a satisfactory manner. Furthermore, it will be noted that the pressure exerted to apply the pressure between the fixed and withdawable contacts comprising the plug and socket is effective through rod 11 to assist in opening the switch 12, thereby accelerating the speed of breaking the circuit. A greater pressure between the electrical contacts during the circuit closing osition is exerted than could reasonably be o tained with the present known types of pll'g and socket contacts.

he compressible and expansible plug per se and the means for varying the pressure between the plug and its socket are not claimed herein apart from the combination thereof with the switch member; said plug and means for varying the pressure between the plug and its socket are the subject matter of my application Serial No. 400,987, filed October 19, '1929, concurrently herewith.

What I claim as. new and desire to secure by Letters Patent of the United States, is,-

1. In electrical switchgear of the drawout type, contact structure comprising a stationary member and a movable member adapted to engage and4 electrically contactwith said stationary member, a switch member coacting with the aforesaid contact structure, and means actuated by said switch member in accordance with its circuit controlling position for varying the contact pressure between said stationary and movable members.

2. In electrical switchgear of the drawout type, a stationary contact, a movable withdrawable portion comprising a contact member for coacting with said stationary contact, a switch member carried by said withdrawable portion, and means actuated by said switch member in accordance with itsl circuit controlling position for affecting the contact pressure between the aforesaid contacts.

3. In electrical switchgear of the draw-out type, a stationary contact, a movable withdrawable portion comprising a contact adapted to coact with and engage said stationary contact, a switch carried by said withdrawable portion adapted to be closed after the aforesaid contacts are in engagement, and means actuated by the switch for further pressing said contacts into engagement with each other.

4. In electrical switchgear of the draw-out type, a stationary socket contact, a movable withdrawable portion comprising a coacting plug conta-ct, a switch member carried by said withdrawable portion, and a member reciproca-Hy mounted with respect to said plug contact adapted to be actuated by said switch member in accordance with a circuit controllinO` position of said member for increasing the contact pressure between said plug and socket contacts.

5. In electrical switchgear of the draw-out type, a withdrawable portion comprising a switch for interrupting the circuit between the live and Withdrawable portions, plug and socket contacts adapted to be engaged and disengaged by movement of the withdrawable portion, and wedging means for increasing the contact pressure between the plug and socket contacts actuated by the aforesaid switch in response to circuit closing movement thereof.

6. In electrical switchgear of the draw-out type comprising plug and socket connecmounted with respect to thestationary portion, a coacting plug connectlon mounted with respect to t el withdrawable ortion, a switch for interruptin the circuit tween the stationary and wit drawable portions, and means res onsive to a. circuit controlling position of sald switch for effecting expansion of the contacting end of said plu thereby increasin the contact ressure tween the plug and lts coacting soc et.

` y 8. The combination with truck type electrical switchgear comprising stationary and withdrawable portions, of electrical contacting structure comprisinga socket connection mounted withv respect to the stationary portion, a hollow plug connection mounted with respect to the withdrawable portion, a switch likewise mounted with respect to the Withdrawable portion for interrupting the circuit between the stationary and withdrawable portions, wedging means disposed centrally of and within said plug connection and adjacent its contactin end, said wedging means resiliently biase to exert expansive pressure at the contacting end of said plug for increasing the contact pressure between said plug and socketl connections, and means for exerting additional bias on sald wedgmg means to 1ncrease the aforesaid pressure in response to closing movement of said switch.

9. The combination with truck type elecl tric'al switchgear comprising stationary and withdrawable portions, of electrical contact .structure comprisin a stationary socket member, a coacting p ug member mounted on the withdrawable rtion, a switch for interrupting the circuit between the stationary ,thccontacting end of het actuated by said switchduring move- Y and withdrawable portions, resiliently biased means for effecting expansion of the contacting end of said plug member, thereby increasing the contact pressure between the same and said socket member, and means responsive tov the circuit closing movement of said switch for further. increasing the aforesaid contact ressure, said last-named means being resilient y biased to assist. inaccelerating the opening movement of the switch.

10. The combination with truck type elecment thereof toits circuit closing position for vfurther increasing the pressure of said resilient means to effect firm contacting en' agement'between said plug and socket mem ers,

. said last-named member adapted to relieve said added pressure u'pon. opening movement of the switch -prior to the separating movement of the plug and socket members. l

11. In electrical switchgear of the draw.

out type, a stationary contact, a movable withdrawable portion comprisinga contact member for coacting with said stationary contact, a switch member carried by said withdrawable portion, and means responsive to opening movement of said switch member prior to separation of said contacts -for decreasing the pressure between said contacts,

thereby facilitating separation thereof.

12. In electrical switchgear of the drawout type, a stationary socket contact, a movable withdrawable portion comprising a plug contact for coacting with said stationary con- Bti tact, a switch member carried by said withtionary and movable contacts when saidswitch is in its circuit closing position, andfor decreasing the aforesaid pressure in response to opening of said switch thereby facilitating withdrawal of said portion.

In vwitness whereof, I have hereunto set my hand this 4th day of October, 1929. 4

4, GEORGE PAILIN.

trical switchgear comprisin stationary and withdrawable portions,v of e ectricalcontact structure comprising a socket member mounted on the stationary portion, a hollow plug member mounted on the withdrawable portion, a switch for intel-ru ting ,the circuit between the stationary andpwithdrawable portions likewise mounted on the withdrawable portion, wedging means disposed within the contacting end of said pl and ada ted to effect expansion of that eii of the p ug for ensuringgood contactin engage thc coactin socket mem r, resilient means for norma y biasing said wedging means into'.pressure-transmittingv engagement with sai plug, and a memment with 

